Why Do Some People Experience Both Hyperthyroid and Hypothyroid Symptoms?

As you know, my practice focuses on helping people with thyroid and autoimmune thyroid conditions.  And while I’d have to say that the majority of patients I work with are solely “hypothyroid” or “hyperthyroid”, there are people who fluctuate back and forth between hyperthyroidism and hypothyroidism.  And so the purpose of this blog post is to discuss some of the reasons for this.

Let’s take a look at four different scenarios that can result in both hypothyroid and hyperthyroid symptoms:

Scenario #1: Having the antibodies for both Graves’ disease and Hashimoto’s thyroiditis.  It’s actually quite common for people to have antibodies for both Graves’ disease and Hashimoto’s.  The antibodies for Graves’ disease are thyroid stimulating immunoglobulins, which is a TSH-receptor antibody.  These cause an overproduction of thyroid hormone by binding to the TSH receptor.  On the other hand, thyroid peroxidase (TPO) and anti-thyroglobulin antibodies indicate that the immune system is causing damage to structures of the thyroid gland.  This can result in symptoms of hypothyroidism, although sometimes they can also result in transient hyperthyroid symptoms, which I’ll discuss next when explaining what Hashitoxicosis is.

So for example, Graves’ disease is characterized by a depressed TSH, elevated thyroid hormones, and elevated thyroid stimulating immunoglobulins.  Most people with this presentation will experience hyperthyroid symptoms.  However, if they also have TPO and/or anti-thyroglobulin antibodies there is the possibility that they might fluctuate back and forth between hyperthyroidism and hypothyroidism.  I can’t say that this fluctuation is common, as usually someone with Graves’ disease is predominantly hyperthyroid, while those with Hashimoto’s usually experience hypothyroid symptoms, although I’ll add that many people with Graves’ disease who also have Hashimoto’s antibodies will eventually become hypothyroid if the autoimmune component isn’t addressed. Keep in mind that it can take years for this to occur.

Scenario #2: Having Hashitoxicosis.  I’ve written a separate article on Hashitoxicosis, but I’ll summarize what it is it here.  Hashimoto’s thyroiditis is typically diagnosed when someone has an elevated TSH along with TPO antibodies and/or  thyroglobulin antibodies.  Many people with Hashimoto’s experience hypothyroid symptoms due to the thyroid hormone levels being either less than optimal or overtly low.  But why do some people experience hyperthyroidism? As I mentioned in the previous article I wrote, the hyperthyroidism experienced in Hashitoxicosis is caused by the release of preformed thyroid hormones caused by the destruction of thyroid follicles.

So these people might feel hypothyroid at times, but then at other times they essentially get a “flood” of thyroid hormone into the bloodstream, resulting in symptoms of hyperthyroidism.  Not only will they feel hyperthyroid, but if they get a blood test during these transient hyperthyroid periods it will reveal hyperthyroidism (low TSH, elevated T3 and T4).  Because of this it’s common for these people to be misdiagnosed with Graves’ disease, but this usually could be confirmed or ruled out by testing the thyroid stimulating immunoglobulins. In other words, if someone has a depressed TSH, elevated thyroid hormones (T3, T4), positive TPO and/or thyroglobulin antibodies, and NEGATIVE thyroid stimulating immunoglobulins, then there’s a good chance that the person has Hashitoxocosis and not Graves’ disease.

Scenario #3: Subacute thyroiditis. I can’t say that most people with subacute thyroiditis experience a fluctuation of hyperthyroid and hypothyroid symptoms, but it is possible.  I’ve also written a separate article on subacute thyroiditis, as this is usually caused by a virus, and the patient initially presents with hyperthyroidism, and over time will become hypothyroid.  So the person starts with hyperthyroidism and then usually becomes hypothyroid within a few months, but unlike Hashitoxicosis, it’s not common for people with subacute thyroiditis to feel hypothyroid one day and then hyperthyroid the next day.  I also should mention the research shows that coronavirus-19 can cause subacute thyroiditis, which I discussed in another article.

Scenario #4: Having Hashimoto’s and another condition that causes tachycardia. Tachycardia is an increased resting heart rate, and while this is a common symptom of hyperthyroidism, there can be other conditions that cause this.  Not too long ago I wrote a blog post entitled “Tachycardia and Thyroid Health“, and here are some of the factors that can cause an elevated heart rate.

• Hyperthyroidism
• Elevated cortisol levels
• Hypoglycemia
• Dehydration
• Hyperkalemia (high potassium levels)
• Hypomagnesemia (low magnesium)
• Hypocalcemia (low calcium)
• Infections
• Anemia
• Caffeine
• Certain medications
• Pregnancy
• Hypoxia
• Postural orthostatic tachycardia syndrome (POTS)
• Histamine intolerance

So for example, if someone has Hashimoto’s and elevated cortisol levels, an infection, or histamine intolerance, they might experience tachycardia at times.  Of course tachycardia isn’t the only symptom of hyperthyroidism, but it’s one of the most common symptoms, and so some people will assume they have hyperthyroidism if they have an elevated resting heart rate.  But if someone experiences tachycardia and every time they get a thyroid panel it looks fine or is more on the hypothyroid side, then the increased resting heart rate probably isn’t caused by hyperthyroidism.

It can sometimes be challenging to figure out what’s causing the increased resting heart rate.  On top of this, the person might have tachycardia and heart palpitations, both of which are common in hyperthyroidism.  But once again, just because someone has tachycardia and heart palpitations doesn’t mean they have hyperthyroidism.  I also wrote an article entitled “Heart Palpitations and Thyroid Health”, and if you read the article you’ll notice that some of the same factors that can cause tachycardia can also result in heart palpitations.

How Do You Treat These Conditions?

In the first two scenarios listed above you would want to focus on improving the health of your immune system.  Regardless of whether someone has the antibodies for Graves’ disease, Hashimoto’s, or both, you want to find and remove triggers, correct underlying imbalances, heal the gut, etc.  Of course this is easier said than done, which is why it’s a good idea to work with a competent healthcare practitioner.

As for the symptom management aspect, this is where it can be tricky.  If someone consistently is hyperthyroid then chances are they will take antithyroid medication or herbs (assuming they don’t receive radioactive iodine or thyroid surgery), whereas if someone is consistently hypothyroid they are likely to take thyroid hormone replacement.  But if they are fluctuating between hyperthyroidism and hypothyroidism then they wouldn’t want to take antithyroid agents or thyroid hormone replacement, and so focusing on the cardiovascular symptoms with a beta blocker or an herb such as motherwort or hawthorn would be an option to consider.

In the case of subacute thyroiditis (Scenario #3), while most people will initially be hyperthyroid for at least a couple of months, many medical doctors are still hesitant to give the person antithyroid medication.  Because of this, many people with subacute thyroiditis will be prescribed a beta blocker.  I don’t have a problem putting my patients with subacute thyroiditis on bugleweed while closely monitoring their symptoms and thyroid hormone levels.  But another option is to refrain from taking any antithyroid agents in this situation and just take something to manage the cardiovascular symptoms.

As for Scenario #4, you of course would want to address the autoimmune component of Hashimoto’s, while trying to figure out the cause of the elevated resting heart rate.  Since there are so many factors that can cause tachycardia it can sometimes seem like you’re searching for a needle in a very large haystack.

To summarize, if you were diagnosed with Graves’ disease and experience both hyper- and hypothyroid symptoms then you most likely fall into “Scenario #1”, although it’s also possible that you actually have Hashitoxicosis and not Graves’ disease.  On the other hand, if you have been diagnosed with Hashimoto’s and experience both hyper- and hypothyroid symptoms then you can fall under “Scenarios 1, 2, or 4”.

Do You Experience Hypothyroidism AND Hyperthyroidism?

If you fluctuate between hypothyroidism and hyperthyroidism I’d love to hear from you!  Do you have the antibodies for both Graves’ disease and Hashimoto’s? Or perhaps you were diagnosed with Hashitoxicosis? Either way I’m sure others who experience the same symptoms would love to hear what your experience has been.